1. Field of the Invention
The invention relates to a control apparatus and a control method for an internal combustion engine.
2. Description of Related Art
Japanese Patent Application Publication No. 2-122255 (JP 2-122255 A) describes a method and a device for measuring, in a gas containing two types of oxygen-containing gases, a relative amount of one of the oxygen-containing gases. In JP 2-122255 A, the oxygen-containing gas (water vapor or carbon dioxide, for example) in the gas is measured by controlling a voltage applied to a cell.
In the field of internal combustion engines, it may be necessary to detect a concentration of sulfur oxide (SOx) in exhaust gas. It may be necessary to detect the SOx concentration of the exhaust gas more widely. Even more widely, it may be necessary to calculate a parameter (a “SOx related parameter” hereafter) relating to the SOx in the exhaust gas. The SOx related parameter is preferably calculated with a high degree of precision.